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Time-gated Sc K-shell and Ge L-shell spectra are presented from a range of characterized thermodynamic states spanning ion densities of 1019–1020cm−3 and plasma temperatures around 2000 eV. For the higher densities studied and temperatures from 1000 to 3000 eV, the Sc and Ge x-ray emission spectra are consistent with steady-state calculations from the modern atomic kinetics model SCRAM. At the lower ion densities achieved through plasma expansion, however, the model calculations require a higher plasma temperature to reproduce the observed Ge spectrum. We attribute this to ionization disequilibrium of the Sc because the ionization time scales exceed the hydrodynamic timescale when the inferred temperatures diverge.
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This content will become publicly available on November 21, 2025
Simultaneous studies of K- and L-shell mid-atomic-number plasmas produced by Z-pinches
Z-pinches have been intensively studied for their applications to high energy density (HED) physics, x-ray sources, astrophysics, and inertial confinement fusion. Alumel (mostly Ni) double planar wire array (DPWA) Z-pinch experiments were performed on the Zebra generator at the enhanced current of 1.6 MA with an advanced setup of diagnostics to measure the temporal evolution of x-ray radiation from plasmas. The implementation of two time-gated spectrometers which recorded hard and soft x-ray radiation allowed for simultaneous studies of K-shell and L-shell radiating plasmas, respectively, in a single experiment. Two almost identical DPWA experiments established a wide observation window around the main x-ray burst. Overall, time-gated plasma spectroscopy provided more information on temporal evolution of ‘hot’ and ‘cold’ K-shell radiating plasmas compared to slowly evolving L-shell radiating plasma. In addition, new spectral features such as from hollow ions were observed and studied using the time-gated K-shell plasma spectroscopy, which is important for further investigation of exotic ion states in HED plasmas.
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- Award ID(s):
- 2205769
- PAR ID:
- 10631554
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- Plasma Physics and Controlled Fusion
- Volume:
- 66
- Issue:
- 12
- ISSN:
- 0741-3335
- Page Range / eLocation ID:
- 125018
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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